Extensive research carried on throughout recent years in methods of human birth control has resulted in the development of various contraceptive means such as, for example, oral contraceptives, intrauterine devices (IUD), diaphragms, and vaginal chemicals adapted for vaginal insertion. Experience has shown that none of these means has been found to be fully safe and satisfactory. Oral contraceptives, for example, developed in the 1950's and commonly know as the "pill", are highly effective and widely utilized today in a world-wide basis. Nevertheless, use of the pill may result in undesirable side effects such as headaches and nausea, and infrequently may be associated with more serious systemic effects. IUD's ordinarily require trained medical help and supervision for proper insertion and maintenance, and have been reported to cause internal bleeding.
Among the most commonly used vaginal chemicals are the spermicidal agents, for example, physiologically acceptable mono(alkylphenyl) ethers of polyethylene glycols wherein the alkyl group preferably contains from 1 to 10 carbon atoms and the polyethylene glycol preferably contains from 2 to 12 ethyleneoxy units, such as nonoxynol-9. These contraceptive agents, which are very often utilized with a diaphragm or other contraceptive device for added contraceptive protection, effectively kill the mammalian spermatozoa thereby preventing the fertilization of the egg. Most often these chemicals are prepared in the form of creams, jellies, suppositories, foams and foaming tablets which are intended to be introduced into the vagina just prior to intercourse.
Considering the above-noted deficiencies as representative, it becomes apprent that in order for any means of providing contraception or birth control to be widely accepted, it must be effective, safe on a short and long term basis, preferably inexpensive and convenient to use.
It is thus an object of this invention is to provide a contraceptive composition for vaginal administration which composition is contraceptively effective for relatively prolonged periods of time after its administration.